U.S. Pat. No. 2,880,435 to Deutsch et al. (hereinafter “the '435 patent”), the entire disclosure of which is incorporated herein by reference, discloses a pipe cleaning cable or “sewer snake” that can be advanced through a sewer pipe as sections of the snake are added on in series. Also disclosed is a wrench for detaching sections when the sewage work is complete. This apparatus is now well known in the industry, and the wrench is typically called a “cable key.”
As set forth in the '435 patent, a cleaning cable 20, best seen here in FIG. 1A and also described with reference to FIGS. 1B-1G, is made up of sections 21 which are joinable one end to another, in series. The assembly is done according to the total length of cable required during the cleaning process. The cleaning cable 20 is adapted to be rotatably moved as it is wormed through a pipe during the cleaning process. Each section 21 comprises an elongate inner helical member 22 and an elongate outer helical member 24. The outer helical member 24 is, at one end, rigidly attached to a male coupler 28. At the other end, it is rigidly attached to a hollow, cylindrical device serving as a female coupler 30. The attachments are by means of threaded engagement with a hollow threaded extension 31 provided on the male coupler 28 and a hollow threaded extension 32 on the female coupler 30. Each end of the inner helical member 22 is attached to an end of a radially surrounding outer helical member 24 by means a respective coupler 28, 30.
The convolutions of the outer helical member 24 that are adjacent to the threaded extensions 31, 32, to thereby engage them, are in juxtaposed relation; whereas, the intermediate convolutions of the outer helical member 24 that span the cable 20 from section joint to section joint are spaced apart to aid in the pipe cleaning process. In particular, a cutting tool may be attached to a coupler at the end of the most remote section 21 of a series of sections. Various types of cutting tools may thereby be attached. As the cutting tool rotatably removes material from an obstruction in a pipe, much of the cut material is carried back out of the pipe by the convolutions of the outer helical member 24 as the cable 20 is rotated.
Even though the cleaning cable 20 remains in substantially the same shape and form, regardless of the torque load applied to it, the cleaning cable is very flexible. This is due to the fact that it comprises flexible helical members 22, 24. It is, therefore, possible to maneuver the cleaning cable 20 through a number of bends, turns and angles as it follows the inner surface of a pipe during the cleaning process.
The male coupler 28 is provided with a flange 50 separating a cylindrical portion 51 from the threaded extension 31. A fixed pin 52, seen also in FIG. 1B for example, is disposed adjacent the end of the cylindrical portion 51. The pin 52 extends diametrically through the portion and projects from it. The end of the cylindrical portion 51 is provided with a tapered portion 53, seen in FIG. 1C.
Intermediate the fixed pin 52 and the flange 50 is a locking pin 54, shown best in FIG. 1D. The locking pin 54 is disposed in a plane substantially parallel to the plane of the fixed pin 52. The locking pin 54 is recessed in a cavity 55 which is closed by a cover 56. The cavity 55 contains a spring 57 which biases the locking pin 54 outwardly.
The coupler 30 is provided with a socket 58 adapted to receive the cylindrical portion 51 of the coupler 28 of another section 21 of the cleaning cable 20. The coupler 30 is provided with diametrically disposed L-shaped slots 60 which are adapted to receive the protruding ends of the fixed pin 52. The inner edge of the mouth of the socket 58 has a beveled portion 62. The beveled portion 62 is adapted to engage the resiliently mounted locking pin 54 and to force it into the cavity 55 against the biasing pressure of the spring 57 as the cylindrical portion 51 is inserted into the socket 58.
The tapered end 53 at the end of the coupler 28 aids in aligning the cylindrical portion 51 with the socket 58. As stated above, the couplers 28, 30 are attachable one to the other as sections 21 of the cable 20 are added one to the other in series relation. The fixed pin 52 of the male coupler 28 is directed through the L-shaped slots 60 as the cylindrical portion 51 of the male coupler is inserted into the female coupler 30. The resiliently mounted locking pin 54 is forced downwardly into the cavity 55 of the cylindrical portion 51 of the female coupler 30 as the cylindrical portion 51 of the male coupler 28 is inserted into the socket 58 of the female coupler 30.
When the fixed pin 52 has abuttingly engaged the end of the longitudinal legs of the L-shaped slots 60 and slidingly progressed through them sufficiently, the male coupler 28 may be rotated, moving the pin 52 along the transverse leg portion of the L-shaped slots. This is best visualized from comparing FIG. 1A to FIG. 1E. As the fixed pin 52 approaches the ends of the transverse legs of the L-shaped slots 60, the locking pin 54 reaches the opening provided by the longitudinal leg of one of the L-shaped slots. The resiliently mounted locking pin 54 is thereby permitted to snap upwardly into the slot 60.
When the locking pin 54 has snapped upwardly, the female coupler 30 is locked to the male coupler 28. This is due to the fact that: a) the locking pin 54 and one of the projections of the fixed pin 52 are disposed in one of the L-shaped slots 60; and b) the other projection of the fixed pin 52 is positioned in the other L-shaped slot. Therefore, the male coupler 28 may not be rotated with respect to the female coupler 30 until the locking pin 54 has been depressed, permitting the locking pin to engage the inner walls of the socket 58 of the female coupler and allowing the fixed pin 52 to move within the L-shaped slots 60. Thus, a spring-loaded bayonet type of joint, or “bayonet connection” 61, is provided to mutually fix the couplers 28, 30 to each other.
The male coupler 28 is manually attachable to the female coupler 30 as follows. The portion of the section 21 is grasped near the female coupler 30. With the other hand, the portion of the other section 21 is grasped near the male coupler 28. The hands are brought together so that the cylindrical portion 51 of the male coupler is inserted into the socket 58 of the female coupler with the fixed pin 52 moving through the slots 60. As the fixed pin 52 moves through the slots 60, the locking pin, by means of the bevel portion 62, is urged downward into a contracted state 64, represented by the downward arrow in FIG. 1D. It is maintained in the contracted state 64 by the closely surrounding inner wall of the socket 58. This clearance permits the cylindrical portion 51 to slide further within the socket 58. When the fixed pin 52 reaches the transverse legs of the L-shaped slots, the male coupler 28 is then rotatable within the socket 58 so that the fixed pin 52 follows the transverse legs. A slight amount of this rotation then allows the locking pin 54 to emerge in the longitudinal leg of one of the slots 60 and thereby lock within that slot. The locking pin 54 is then in a “locked state.” A number of sections 21 can thereby be assembled in series.
When it is desired to uncouple the female coupler 30 from the male coupler 28, a disassembly wrench 93, seen from FIG. 1F, may be employed to undo the bayonet connection 61. The wrench 93 has, at one end, an arcuate portion 94 that is terminated with an inward projection 95. For the uncoupling operation, the wrench 93, as seen in FIG. 1G, is fitted to the couplers 28, 30. This is typically done with the wrench 93 being held in one hand. In particular, the arcuate portion 94 surroundingly engages the female coupler 30, with the projection 95 forcibly depressing the locking pin 54 below, or possibly flush with, the outer surface 97 of the cylindrical portion 51 of the male coupler 28. Thus, the locking pin 54 is now in a depressed, or “unlocked”, state. The other hand now grasps, or continues to grasp, the other section 21 which provides the male coupler 28. The wrench 93 is therefore usable torque-wise to axially twist the two sections 21 with respect to each other. The rotation maintains the locking pin 54 in the contracted state 64 even when, by virtue of the rotation, the locking pin is no longer in contact with the projection 95. As the rotation progresses, it brings, relatively speaking, the fixed pin 52 along the transverse legs of the L-shaped slots 60. Ultimately, the fixed pin 52 reaches alignment with the longitudinal legs of the L-shaped slots 60. At this stage, the hand holding the wrench 93 can switch to grasping the section 21 attached to the female coupler 30. With the slot 60 thereby cleared of the projection 95 and with the fixed pin 52 free to be slid through the respective open ends of the longitudinal legs of the slots 60, the fixed pin is withdrawn through the slots by manually pulling the two sections 21 apart.
With the two sections 21 now uncoupled, the section that provided the female coupler 30 is pulled to let another bayonet connection 61 emerge from the pipe.
The operation is now repeated. This involves picking up the wrench 93 once again. The other hand grasps the section 21 providing the male coupler 28 (i.e., the same section that provided the female coupler 30 in the just-previous joint uncoupling step). The wrench 93 is used to relatively twist the sections 21 into position. At this point the wrench is manually released. The releasing hand grabs the section 21 just rotated by the wrench 93. The sections 21, one in each hand, are pulled apart manually.
The complete operation of withdrawing more of the pipe cleaner 20, picking up the wrench 93, using it, putting it down, and pulling the sections 21 apart continues until the entire pipe cleaner is disassembled.